JPS62156573A - Charging testing device for cable - Google Patents

Abstract

PURPOSE:To make it unnecessary to provide an expensive blocking coil in an air space part by containing a blocking coil in an air cable head for charging a sample cable. CONSTITUTION:The titled testing device has a structure which has installed a blocking coil 7 in a high voltage conductor part 8 of a mini-clad type air terminal part of a sample cable 4. Also, both terminals of this coil 7 are connected to electrodes 9A, 9B of a movable type, which are opposed by a short circuit or a small air-gap 10, in said coil. Moreover, a part of the sample cable or a cable 4a whose insulating performance is more excellent than said cable is connected to one terminal of the coil 7, and made to execute an operation of a coupling capacitor. Also, a mini-clad type terminal 12 is provided on the terminal of the sample cable 4, a partial electric discharge detecting resistance 5 is connected to a sheath side of the sample cable 4, and a voltage of both its ends is led to a partial electric discharge measuring instrument 6 and measured.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cable energization testing device, and more particularly to a cable energization testing device for performing partial discharge and withstand voltage tests on high voltage CV cables, etc. It is.

[Prior Art] As shown in Figure 3.4 in Section 3.4, conventional power charging test equipment that performs partial discharge and withstand voltage tests on high voltage cables under test, for example, uses In order to remove noise from the high voltage power transformer 1, which is a transformer of A partial discharge detection resistor 5 was connected between the test cable 4 and the ground, and the voltage at both ends was measured using a partial discharge measuring device 6.

[Problems to be Solved by the Invention] By the way, in the conventional voltage application test device shown in Fig. 3.4 above, as the applied voltage increases, the coupling capacitor 3
The voltage applied to the filter, that is, the withstand voltage, also increases, and since there is a blocking coil 2 on the high voltage side, the part of the filter that can withstand this becomes large and expensive, and the space for insulation also becomes large. Was.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cable energization testing device having a portion of a high-voltage noise removal filter that requires less insulation space and eliminates the above-mentioned conventional drawbacks.

[Means and Construction for Solving the Problems J1 In the present invention, a mini-clad type cable head used for partial discharge tests or dielectric breakdown tests of test cables is skillfully utilized, and the aerial cable head portion of the head is A blocking coil is inserted into the high voltage conductor section.

[Example] The present invention will be described below with reference to an illustrated example. 1st
As shown in the schematic diagram of the configuration of the figure, the energization test device according to the present invention has a structure in which a blocking coil 7 is installed within the high voltage conductor portion 8 of the mini-clad type air terminal portion of the test cable 4. . Both terminals of the coil 7 are connected to movable electrodes 9A and 9B that are opposed to each other with a short circuit or a slight gap 10 within the coil. Also,
A part of the cable under test or a cable 4a with better insulation performance is connected to one end of the coil 7 through a mini-clad type connection part 11 to perform the function of the conventional coupling capacitor 3. Then, a mini-clad type terminal 12 is provided at the end of the test cable 4, a partial discharge detection resistor 5 is connected to the sheath side of the test cable 4, and the voltage at both ends is led to a partial discharge measuring device 6 and measured.

As shown in FIG. 2, the blocking coil 7 is wound around a winding core 13 made of an insulating cylinder.

That is, the insulating core 13 is disposed within an insulator 16 whose lower part is fixed to a metal fitting 14 and its two parts are fixed to a flange 15, and the blocking coil 7 is tightly wound around the outer peripheral surface of the core 13. and is surrounded by a high voltage insulating layer 17. The movable electrodes 9A and 9B are arranged in opposition within the winding core 13. This electrode 9A
, 9B are formed in a spherical shape and are attached to opposite ends of discharge rods 18a and 18b inserted into the winding core 13 from above and below. Both ends of the blocking coil 7 are connected to both rods 18a and 18b, respectively. In addition, the code|symbol 19 is an external shielding member.

Furthermore, in the above configuration, the organic insulating winding core 13 is porous and the atmosphere inside the winding core may diffuse into the outer high voltage insulating layer 17 as shown in the figure.
The core 13 is filled with an insulating medium 21, which isolates the inside of the core from the outside air.

Next, specific experimental examples of the present invention will be described.

A diameter of 15 cm is attached to the high voltage conductor part of the above cable air terminal.
Using a winding core with an effective length of 500 cm, if an enameled wire with a diameter of 1.6 mm is tightly wound around the outer circumferential surface as the blocking coil 7, it can be wound approximately 2800 times, the inductance is 3.4 mH, and the partial discharge measurement frequency If IMIIz, then the glue actance is 2
1 becomes Ω.

In addition, if a 200PF/m cable with a length of 10m is used as the cable 4a (see Figure 1) that serves as a filter capacitor and a coupling capacitor, the IMI (
The capacitive reactance at Z was 80Ω, and the noise from the high voltage power transformer 1 was reduced by 48db.

As described above, according to the present invention, a filter for noise removal can be constructed without using a dedicated blocking coil and a filter capacitor, and moreover, no installation space is required.

Also, in the unlikely event that the test cable experiences insulation breakdown, the gap 1
Another advantage is that if you protect it with 0, you can avoid damage to the blocking coil. In other words, it becomes possible to measure partial discharge immediately before dielectric breakdown.

It goes without saying that the inductance can also be increased by inserting a high-frequency iron core inside the winding core 13 of the blocking coil.

[Effects of the Invention] As described above, in the present invention, since the blocking coil is built into the aerial cable head for charging the test cable, there is no need for an expensive blocking coil in the aerial space. This has the remarkable effect of eliminating the need for an air space, and provides a cable energization test device that eliminates the drawbacks of the conventional cables.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the configuration of a cable electrification testing device showing an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the core structure of a blocking coil used in the energization testing device, and FIG. 4 is an electric circuit diagram showing a partial discharge measuring circuit for high voltage cables, and FIG. 4 is a schematic diagram of the configuration of a conventionally used cable electrification testing device. 7・・・・・・・・・・・・・・・Blocking coil 8・・・・・・・・・・・・High voltage charging conductor part 9A
, 9B... Movable electrode 13... Winding core patent applicant Hitachi Cable Co., Ltd. Fang 1 Shimu 30

Claims (2)

[Claims] (1) In a cable energization test device that performs partial discharge and withstand voltage tests on a high-voltage cable under test using a mini-clad cable head, the high-voltage energized conductor in the aerial head portion of the mini-clad cable head is A cable energization testing device characterized in that a blocking coil is inserted into the cable, and both terminals of the blocking coil are opposed by movable electrodes that are short-circuited or have a slight gap. (2) The core of the blocking coil has a structure in which an airtight insulating tube is used to separate the airtightness of the inside and outside of the core, and the movable electrode is placed inside the core. A cable energization test device according to claim 1, characterized in that: